The push by Representative Greg Harris and Senator Heather Steans, both Chicago Democrats, comes just 18 months after the state started allowing civil unions for same-sex couples. Harris and Steans on Thursday said gay marriage has been rapidly gaining speed since President Barack Obama spoke in favour of it earlier this year.

The legislators declined to detail the status of roll-call votes in each chamber during a conference call with reporters.
But Harris has previously said he wouldn't bring a bill to the floor without assurances that there are enough votes to pass it.

"We're in striking distance of being able to get it done," Stearns said.

Harris and Steans played major roles in bringing civil unions for domestic partners to Illinois. Voters in four other states either endorsed gay marriage or repudiated bans on it in the November election.

Chicago Mayor Rahm Emanuel calls it a legislative priority. A poll for Southern Illinois University in September found 44% of Illinois voters support same-sex marriage, up 10 points from just two years earlier.

Reaction from religious groups
"It's very straightforward," Harris said. "We treat all couples with the same respect and dignity in the eyes of the law and we protect the rights of religious institutions to either consecrate or not consecrate marriages within their faith as they see fit. It's very important that government not involve itself in religion on either side of the issue."

However, the Catholic Conference of Illinois opposes the measure and a conservative Christian group's lobbyist says he considers passage now to be a bigger stretch than advocates believe.

Stearns soft-pedalled on Thursday when asked if the move to propose legislation signalled that supporters predict victory.

"That's a dangerous game, but that's the goal. We really do want to get a bill to the governor in January ...," she said.

Nine states currently allow gay marriage. Harris and Steans said an Illinois law, which would take effect July 1, would recognise same-sex marriages from other states, and those who have entered civil unions in Illinois could apply for a marriage license with no fee for the first year.

Camilla Taylor, marriage project director for Lambda Legal, which is representing 25 couples in a lawsuit opposing the state's gay-marriage ban, said the announcement on Thursday "brought hope to thousands of same-sex couples across Illinois".

"Illinois same-sex couples and their children need the freedom to marry now, and it's encouraging that our elected officials agree," Taylor said.

While backed by prominent Democrats, the issue is not strictly a partisan one. Opponents to civil unions in 2010 included some southern Illinois Democrats, while some suburban Republicans supported it.

"Marriage is not something government has instituted. Marriage is something that's instituted by God," Vanden Bosch said. "People, rather than conforming their lives to the law of God, want to conform the law to their lives."

The Catholic Conference of Illinois, which represents 3.8 million Catholics in the state, has produced a "marriage toolkit" it's distributing to churches and schools outlining the church's position on the issue.

"Nature gives us two sexes for a reason; that's why marriage is unique," conference executive director Robert Gilligan said. "As much as this can be a religious issue, same-sex marriage goes against nature."

The contest for votes in the next three weeks promises to be heated, even as the plan battles for attention among a laundry list of major issues facing lawmakers in the six-day "lame duck" session before a new General Assembly is sworn in.

Among the other issues under consideration are plans to fix the pension system, provide driver's licenses to immigrants, legalise medical marijuana and close budget shortfalls.

Winds of change
"We are dedicating our efforts to leaving no stone unturned in helping them" secure passage, said Bernard Cherkasov, chief executive of Equality Illinois. "Our members and supporters by the thousands will be contacting lawmakers."

Harris claims it's been happening already, and some formerly stubborn attitudes among his colleagues have been changed by constituents.

"One of the things that moves them is when they've known the family and they've known three generations of the family and the parents, the grandparents and the kids come in and say, 'Why would our state treat our lesbian granddaughter with less respect than our straight grandson, and how can you support that?'" Harris said. "That's very compelling." – Sapa-AP